Share capital - Stock options outstanding (Details)	6 Months Ended
	May 31, 2022 $ / shares shares
Share-based Payment Arrangement, Option, Exercise Price Range [Line Items]
Number of outstanding options | shares	12,187,150
Weighted average years to expiry	2 years 10 months 28 days
Weighted average exercise price options outstanding	$ 2.50
Number of exercisable options | shares	9,874,312
Weighted average exercise price exercisable	$ 2.52
Number of unvested options | shares	2,312,838
$1.01 to $1.50
Share-based Payment Arrangement, Option, Exercise Price Range [Line Items]
Exercise price lower range limit	$ 1.01
Exercise price upper range limit	$ 1.50
Number of outstanding options | shares	870,000
Weighted average years to expiry	6 months 7 days
Weighted average exercise price options outstanding	$ 1.05
Number of exercisable options | shares	870,000
Weighted average exercise price exercisable	$ 1.05
Number of unvested options | shares	0
$2.01 to $2.50
Share-based Payment Arrangement, Option, Exercise Price Range [Line Items]
Exercise price lower range limit	$ 2.01
Exercise price upper range limit	$ 2.50
Number of outstanding options | shares	2,599,500
Weighted average years to expiry	3 years 10 months 2 days
Weighted average exercise price options outstanding	$ 2.26
Number of exercisable options | shares	1,676,498
Weighted average exercise price exercisable	$ 2.29
Number of unvested options | shares	923,002
$2.51 to $3.00
Share-based Payment Arrangement, Option, Exercise Price Range [Line Items]
Exercise price lower range limit	$ 2.51
Exercise price upper range limit	$ 3.00
Number of outstanding options | shares	6,920,150
Weighted average years to expiry	2 years 11 months 12 days
Weighted average exercise price options outstanding	$ 2.64
Number of exercisable options | shares	5,530,314
Weighted average exercise price exercisable	$ 2.66
Number of unvested options | shares	1,389,836
$3.01 to $3.41
Share-based Payment Arrangement, Option, Exercise Price Range [Line Items]
Exercise price lower range limit	$ 3.01
Exercise price upper range limit	$ 3.41
Number of outstanding options | shares	1,797,500
Weighted average years to expiry	2 years 6 months 21 days
Weighted average exercise price options outstanding	$ 3.03
Number of exercisable options | shares	1,797,500
Weighted average exercise price exercisable	$ 3.03
Number of unvested options | shares	0